(a) Field of Invention
The present disclosure of invention relates to a thin film transistor array panel and a manufacturing method thereof. More specifically, it relates to formation of thin film transistors having a semiconductive oxide layer as their active layer.
(b) Description of Related Technology
It has become desirable to make computer display monitors and televisions thin and lightweight, and pursuant to such desire, cathode ray tubes (CRT) are being replaced by liquid crystal displays (LCDs) or organic light emitting devices (organic light emitting diode (OLED) displays). The liquid crystal panel part of an LCD system is a light-shuttering non-emissive device while the organic light emitting device (OLED display) is a self-emissive device. However they both include a thin film transistor array panel having a thin film transistor provided as a switching element per each individually addressed pixel unit.
The thin film transistor typically includes an active switching region (e.g., a semiconductor region) defining a channel area disposed between source and drain areas. However electronic characteristics of the active switching region (e.g., of the semiconductor material) may be detrimentally changed by the specific photolithography and etching processes used for forming different thin films, and the performance of the thin film transistor may be correspondingly deteriorated when the characteristics of the active region are detrimentally changed. Particularly, in the case where the active switching region includes a semiconductive oxide, if the channel-defining layer is exposed to moisture (e.g., water vapor), or external contaminating ions, or to oxygen during the manufacturing process of the thin film transistor, a corresponding chemical oxidation or reduction reaction may occur and may cause the electrical conductivity characteristics of the semiconductive oxide region to be adversely changed.
The above information disclosed in this Background section is only for enhancement of understanding of the technological background and therefore it may contain information that does not form the prior art that is already known or recognized by persons of ordinary skill in the pertinent art.